Bolt catch devices for hand-held firearms are known in the art, especially in handguns and combat rifles. The purpose of a bolt catch device on any firearm is to retain the principal members of the bolt or bolt carrier mechanism in a rearward position. The rear-hold position is desirable as a safety measure to allow an unobstructed view of the chamber of a firearm; to provide access to the chamber area for cleaning or clearing an obstruction, or other maintenance; as a signal to the operator that the magazine is empty; and to provide a means for rapid reloading, by holding the bolt group to the rear while the empty magazine is removed and a new magazine is installed.
Some members of the M16/M4 family of firearms have a bolt catch that is actuated so that it holds the bolt group rearward after the last round is fed from the magazine.
When the bolt catch device is actuated manually the bolt group is released and allowed to move forward under spring pressure, chambering the first round from a new magazine.
On most firearms the bolt catch is located on one side of the receiver, making it difficult and sometimes impossible to actuate with a single hand while aiming the firearm. On the M16/M4 rifle, for example, the bolt catch is on the left side of the receiver where actuation is generally accomplished with the palm of the left hand, when the firearm is held on the right shoulder. The design of the M16/M4 bolt catch is such that it is a single element functioning at one end as the component holding the bolt group rearward and at the other end offering a knurled protrusion on the end of a lever as a point for actuation.
Ambidextrous bolt catches are found almost exclusively on semi-automatic pistols, and take the form of a latch or other device that keeps the slide to the rear after the last round is fired.
The known prior art includes several patents describing bolt catch device arrangements for firearms or ambidextrous magazine catch and release mechanisms that are used in a clip change when the last round is fired from a magazine. The function of a bolt catch device is significantly different than the function of a magazine catch, but the use of an ambidextrous means for operating each mechanism is the reason for including such prior art in the list below.
U.S. Pat. No. 3,540,142 to Vartanian et al. describes a bolt stop mechanism for a semi-automatic firearm with a spring that engages the bolt stop to bias against a pin. The bolt stop is pivotally mounted in the firearm receiver and is movable into and out of engagement with the bolt by pushing the end of the latch and releasing it.
U.S. Pat. No. 3,750,531 to Angell et al. requires a safety lever to be pushed up to a horizontal position, the action operates to lock the strike to prevent it from traveling down the striker tunnel in a dual protection safety device for semi-automatic pistol.
U.S. Pat. No. 4,429,479 to Johnson describes a magazine latch release mechanism for repeating rifles.
U.S. Pat. No. 4,521,985 to Smith et al. shows an ambidextrous magazine release.
U.S. Pat. No. 4,620,134 to Beretta describes a retaining mechanism for rifle magazines, wherein a hook is engaged in the slot of a magazine that is fixed to a spring-loaded arm located transversely in the body of the weapon; the hook can be operated from both sides of the weapon.
Garrett in U.S. Pat. No. 5,519,954 uses two springs, houses the pivoting mechanism in a protruding base and is specifically designed for use as an ambidextrous magazine release.
U.S. Pat. No. 5,636,465 to Johnson describes a spare magazine carrier. FIG. 8 shows a plunger mounted within a tubular housing and biased outwardly, or leftward, by a helical spring surrounding a portion of the plunger.
U.S. Pat. No. 5,726,376 to Menges et al. in FIG. 1 shows locking levers with catching shoulders to prevent accidental firing of weapon.
U.S. Pat. No. 5,741,996 to Ruger et al. in FIG. 2 shows a slide and a slide stop latch.
U.S. Pat. No. 6,257,114 to Murello describes a firing lever mechanism for firearms with a locking lever pivotally mounted that cooperates with a slide and stop pin that is engaged to lock the slide into position.
U.S. Pat. No. 7,047,864 to Spinner et al. FIG. 4 and FIG. 5 show a magazine shaft with cross boring, swivel shaft with levers, a catch on lever, left-handed shooter holding the weapon with left hand can now press on the pivoting lever and release the slide unit for forward movement.
U.S. Pat. No. 7,103,998 to McGarry describes a camblock assembly for a firearm having a guide rod to resist movement of a reciprocating slide.
U.S. Patent Publ. No. 2003/0208940 to Johnson describes a bolt catch operating lever attached to the left side of receiver with a pivot pin. The bolt catch engages the bolt to hold it in a rearward position using a detachable lateral extender mechanism; lever is pressed to the right, the catch is disengaged and releases the bolt that is moved forward by a spring.
U.S. Patent Publ. No. 2005/0000138 to Kiss in FIG. 2 and FIG. 5 shows a bolt catch device pivotally mounted on a rivet; the lever connects with and transverse the channel shaped receiver with bottom wall; there is a return spring; a sensor lever rotates the catch device upward; the head of the lever is returned by spring forces of the magazine and inhibits the forward movement of the carrier locking the bolt carrier.
Garrett in U.S. Patent Publication 2006/0,123,683 describes an ambidextrous magazine catch having a rod with a threaded portion that is pivotally attached to a lever and guided transversely through an orifice. The ambidextrous magazine catch has a single spring, engages and disengages the magazine slot of magazine by depressing lever.
The above patents disclose the state of the art in relation to bolt catch devices and ambidextrous magazine catches or releases for firearms; however, with regard to bolt catch devices, there is still a need for an ambidextrous, quick, easy to secure, reliably functioning bolt catch device to retain the bolt and bolt carrier mechanism in a rearward position after the last round is fed from the magazine.
Improvements are needed so that a bolt catch device can be engaged with ease and dexterity with one hand by either a right-handed shooter or a left-hand shooter of a weapon. Such an improvement saves valuable time in the field and significant costs in inventory. There is no longer a need for different weapon assemblies based on whether a shooter is right-handed or left-handed. Such improvements will mean that weapons are safer and universally acceptable to all users; the present invention meets these needs.